Paul max stephan



P. M. STEPHAN.

FULLCIRCL COLLAPSIBLE RETREAD MOLD. APPucATloN HLED JULY 19. 1918.

1,807,798. Patented' June 24,1919.

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l /brngyot thus insuring which 1s nia UniTED sTATEs PATENT oEEicE.

PAUL MAX STEPHAN, 0F FRANCISCO, CALIFORNIA.

FULL-CIRCLE connnrsrinnn-nrTinian-Morin.l

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Specification of Letters Ijatent. Patented June 24, 1919,

Application led July 19, 19178. SerialNo. 245,620.

To all whom t may concern Beit knewn that'l, PAUL Miur STEPHAN, acitizen of the United States, residing at'the city and county of SanFrancisco and State of California, have invented new and usefulimprovements in Full-Circle Collapsible Rctread-Molds, of which thefollowing is a specification.

This invention relates toa retread mold for use in connection withpneumatic tires.

lit is the custom at the present time to remodel pneumatic vehicle tirecasings when they have become worn,and to supply them with a ynew'tread. This operation has been accomplished by curing layers of rubber,ap-

. plied to the tread in molds representin a` segment of the tirecircumference. This as .resulted in producing soft spots in the retread,as well as requiring considerable time and skill in the operation.

It is the`princip"al object ofthis invention to provide a retread moldwithin which sev-- eral tires of diierent sectional sizes and diametersmay betreated, and which will insure a continuous retread at 'oneoperation,

in a fraction of the time rev quiredby most other methods.

The present invention contemplates the use of an annular retread moldformed of complementary halvesV adapted to encom- 1 pass a complete tirecasing, and to cure said seen through the complete curing mold, and'Afurther disclosin 'the clamping apparatus holding a tire wit in themola. 4,

F' g. 2 is a -view in' section as seen on line 2f-2, Fig. 1,illustrating thc clamping device and the curing mold. l

Referring more particularly to the drawings, 10 and 11 indicate .theseparate halves of the curing mold. Thesehalvesare comlementary and whencombined as shown in ig. 1 form a complete yencircling jacket for themem

neumatic tire 1 2; E ach of the mold ers arevformed with a double walltoprovide an intervening steam circulating i.

a tread of uniform texture,`

permeated .with heat and uni-V passageway 13. At one side of tliedevicev the mold members are formed with hinge brackets, which arepivotallyunited by a hinge pin 14. The opposite or free ends of the molds areadapted to be locked together by locking bolts 15 swiveled to the lowermold 11 and. provided to swin into engage ment with lugs 16 upon the ege of the upper mold. In the resent instance the lower mold is rigidlyhe d upon standards 17 although other lixtures niight be used. The.

two circulating passageway'sA 13 of the mold sections are incommunication with the steam generator 18 by means of a connect ingconduit 19. This member is fitted with a control valve 20. 1 The conduit19 supplies steam to the circulating` passageway in the lower` casingmember.v Pipes 21 and 22 are provided lto conduct the steam from thelower circulating passageway and the upper also. shown in Fig. 2, andthus the mold halves may be swung in relation to each other withoutinterrupting the supply of steam tliereto. A return of the condensedsteam may be effected through a drain pipe 23 lng from the lowermostportion of the circulat-A ing -passageway 13 in the lower mold half.

Theupper half of the mold is drained by 'a pipe 34 which communicateswith the steam jacket near the hinge and a pipe 35 communicating withthe opposite end of the steam .jacket on this upper half. The pipe 34 issecured by a swivel joint to a drain These pipes have .a 'swivel jointas pipe 36 which empties into the lower steam jacket.` This pipe is alsoin communication,

with the pipe 35. By this arrangement the two intercommunicating pipes.between the separate mold parts may yield to allow the mold to |beopened. It is highly desirable that tires of, various diametersbetreated 'with a single mold. This is especially true in view of the factthat a tire stretches in use, and may be :from 10 to 20% larger indiameter than its original dimension. Y

ioo

The present device has-been designedzto Y accommodate certain groups oftires, as for f instance, tires measuring 31x4, 30X3}'.'

and 30x3. These three V sizes are accommodated by the useof a shell 25which fits within the crescent sha ed annular recess of j the curingmold. It will be understood that the curing mold is semi-circular insection as shown in' Fig. 2, and that aress corres onding'to the outercontour of a tire is t us formed. By Athe of rings of a diff ferentcontour the casing' treated may be firmly interposed, and, at the sametime,

rigidly mounted Within the curing mold.

It is a common practice to it the casing with an air bag or sand bag 26.This bag is positioned within the casing, and takes the .Y

thereof. lVhen this is in proper condition the casing is positionedwithin the shell 25, and thereafter inclosed by@ the vcuring moldcomprising the halves 10 and 11. A sand bag is placed within the casingand the clamping ring 27 positioned thereagainsa This ring may be splitin one or more places to allow it to freely expand. IVhen the ring is inplace it may be rigidly clampedagainst the sand. bag by the set screws28. The power exerted by these screws will hold the casing rigidlv.Steam may then be admitted through the pipe 19, and will circulatethrough the chamber 13 of the lower casing mem'ber through pipes 21 and22 and a s ilnilar chamber in the'upper casing member.

A gage 30 may be`used to indicate'the pressure of the steam within themold. This pressure may be maintained until `the mold is thoroughlyheated, and will thereafter impart the heat to the tread. Continuousapplication of this heat will cure the retread portion and render thetire suitable for further use. 4

Attention is directed to the fact that treads of different designs maybe produced and cured, and that by the arrangement here shown the exactarea upon the tread may be treated without damaging the rubber adjacentthereto.

It will thus be observed that by the use of the present device a fullcircle curing action may be provided to produce a retread of uniformdensity and thickness in a rapid manner.

Having thus described my invention, what I claim and desire to secureby. Letters Patent is:

1. In a retread mold, a pair of superimposed tire encirclin members eachof semicircular form, sai members being hinged together at one of theirends and being arranged vertically so that their ends meet in ahorizontal plane, each member having a semi-circular chamber therein asteam suply pipe leading from one en of the chamiier of the lower memberto the adjacent end of the chamber of the upper member, a drain pipeleading from said end 0f the chamber of the upper member to said end ofthe chamber of the lower member, a drain pipe leading downwardly fromthe other end of thechamber of the .upper member into said first-nameddrain pipe, anda drain pipe extending into the chamber of the lowermember at the lowest point of the chamber.

2. A retread mold including a pair of hinged tire encircling members,means to supply heat to the members, a pressure ring arranged within themembers, a sectional ring interposed between the pressure ring and thetire encircling members, and radial set screws eXtendin through thepressure ring and engaging te respective sections of the sectionalringso as to effect adjustment of the latter.

3. A retread mold including a pair of hinged tire encircling members,means to supply heat to the members, a pressure ring arranged within themembers, a sectional ring interposed between the pressure ring and thetire encircling members, and independent operable means between thepressure ring and the sections to allow of var1- able adjustments of thelatter.

In testimony whereof I have hereunto set my hand in the presence of asubscribing witness.

PAUL MAX STEPHAN. Witness:

W. W. HEALEY.

